Response indicating electromagnetic device



April 1957 J. STOECKLIN ETAL 2,787,689

RESPONSE INDICATING ELECTROMAGNETIC DEVICE Filed Aug. 8, 1955 2 Sheets-Sheet l Q z\\\\l ggamqbl I gm? 3! a i 8 '3 fa. 5' 6 HA.

mvsmons ATTORNEY 5 RESPONSE INDICATING ELECTROMAGNETIC DEVICE Filed Aug. 8, 1955 April 2, 1957 J. STOECKLIN ETAL' 2 Sheets-Sheet 2 INVENTORS M f QM/(1 ATTORNEY 5 United States Patent RESPONSE INDICATING ELECTROMAGNETIC DEVICE Josef Stoecklin, Ennetbaden, and Erwin Drack, Nnssbaumen, Switzerland, assignors to Alrtiengesellschaft Brown, Boveri & Cie, Baden, Switzerland, a joint-stock company Application August 8, 1955, Serial No. 527,058

Claims priority, application Switzerland September 22, 1955 3 Claims. (Cl. 200-167) This invention relates to a response indicating electromagnetic device and more particularly to relays or electromagnetic switches having indicators which show visually the condition of the relay contacts.

Electrical devices, for example electromagnetic switches employed in protective relay circuits are frequently provided with indicators to show the open or closed condition of the switch contacts and, in general, such indicators are re-set manually to their initial position simultaneously with the restoring of the relay contacts to normal condition. In the case of a relay for closing contacts in a signal or control circuit in the event of a current pulse in excess of a preselected magnitude, it is essential that the indication of relay actuation should be displayed only when the contacts are actually engaged. It is therefore practical and customary to employ the contact-actuating element of the switch to move the indicator. Since the contact-actuating element usually moves only a short distance, it has been proposed to locate the indicator back of a plate provided with several staggered slots which each have a width equal to the distance travelled by the contact-actuating element. The disadvantage of this arrangement is that considerable space is required to provide an indication of substantial effective area which will be clearly visible at a distance from the relay.

Objects of the present invention are to provide electromagnetic switches having indicators which are displaced a distance substantially greater than the movement of the armature or other contact-actuating element. More specifically, an object is to provide an electromagnetic switch or relay having an indicator plate which is initially displaced by the relay armature as it moves to actuate the relay contacts, and is then displaced a further, and preferably a greater step, by a spring loaded combination latch and release mechanism which retains the relay position indicator in the signal condition until manually re-set to initial condition.

These and other objects and the advantages of the invention will be apparent from the following specification when taken with the accompanying drawings in which:

Fig. l is a front elevation of a response indicating electromagnetic switch embodying the invention;

Fig. 2 is a side view of the same, with parts in section on the plane of line 2--2 of Fig. 1;

Fig. 3 is a side view, like Fig. 2, but showing the switch contacts and indicator in actuated condition;

Fig. 4 is a fragmentary transverse section on line 4-4 of Fig. 2, with the latch for the indicator plate in the position occupied when the switch contacts are open.

Fig. 5 is a view similar to Fig. 4, on line 55 of Fig. 3, showing the latch and indicator in the positions occupied when the switch contacts are closed.

Fig. 6 is a front view of the indicator plate.

Fig. 7 is a perspective view of the indicator plate as seen from the rear; and

Fig. 8 is a sequence of schematic views illustrative of the two-step movement of the indicator.

In the drawing, the reference numeral 1 identifies a.

front plate of insulating material which supports pairs of spaced stationary contacts 2, 2a and is secured by screws 3 to a block 4 of insulating material and to the forward flange 5 of an inverted U-shaped bracket which carries a solenoid 6. The plate is provided with an upper opening or window 1a for the display of an indicator which will be described later, and with a lower opening lb. Movable contact bridges 8 for spanning the contacts 2 and 2a of each pair have stems 8a which extend through the opening 1b of the front plate and are embedded in block 9 of insulating material which is slidable vertically between the front plate 1 and the bracket 5. The solenoid armature 10 is a soft iron plate having its rear end hinged on the rear flange 5a of the solenoid supporting bracket and its front end seated in a transverse notch 9a of the insulating block 9. The combined weight of the contacts 8, block 9 and armature 1|] biases the contacts 8 into their lower position, as shown in Figs. 1 and 2, and they are lifted into actuated position to complete the circuits between contacts 2 and 2a of each pair, as shown Fig. 3, on energization of the solenoid 6.

The illustrated switch is of the double-pole single throw type and is normally open but it is to be understood that the invention is not limited to a contact system of this type or to a normally open switch.

In accordance with the invention, the front face of the block 4 is grooved vertically to provide a guide channel 40 for a vertically movable indicator plate 11 which drops of its own weight and normally rests on the insulating material block 9 in the initial open position of the switch. The rear of the indicator plate 11 is provided with a recess having a surface with an initial upper portion llu parallel to the direction of vertical sliding movement of the indicator plate and an inclined portion 11b which extends downwardly into proximity with the recess base surface llc which is horizontal, i. e. perpendicular to the direction of sliding movement. As seen in Fig. 6 the lower half 11d of the front face of the indicator plate is colored such as for example red and the upper half lle is uncolored.

A combined latch and re-set plate 12 is slidable horizontally in a slot 4b provided in the block 4 of insulating material. As shown in Figs. 4 and 5, the plate 12 includes a portion 12a which projects beyond the side wall of block 4 and is adapted to be pressed in by the operator to release and drop the target indicator plate. A rear positioned shouldered portion 12b is engaged by one end of a helical spring 13 which biases the reset plate in the direction tending to move the manually actuated reset portion 12a outwardly of the block 4. A front positioned shouldered portion 120, as shown in Fig. 8, is entered into the recess in the indicator plate 11 and bears against the surface portions 11a, 11b.

Operation When the solenoid 6 is deenergized the armature It) occupies its lower position and likewise the insulating block 9, contact members 8 and indicator plate 11 occupy their lower positions. Such positions are indicated in Fig. 2 and it will be observed that the lower face of the indicator plate 11 lies in contact with the upper face of the insulating block 9. In the sequence views of Fig. 8 the corresponding positions are indicated at a and it will be observed that shouldered portion 12c bears against the portion 11a of the recess in indicator plate 11. The upper, uncolored top half lle of the front face of the indicator plate is aligned with the window In in the front plate 1.

As soon as solenoid 6 is energized, armature 10 moves upward to the position indicated in Fig. 3 raising block 9, indicator plate 11 and contact bridges 8 so that the latter engage the fixed contacts 2, 2a. Block 9 and indicator plate 11 have now reached the positions shown at .5 in Fig. 8 from which it will be observed that the shouldered portion 120 of the latch plate now bears against the inclined surface 11b of the recess in the indicator plate. Since the force of spring 13 is always exerted on the latch plate 12 in the direction indicated by the arrow when viewing Fig. 8, plate 12 will now be caused to move upward until it reaches the signal position shown at rin Fig. 8 and wherein the lower, colored half ill! of the front face of the indicator plate is now visible in the window In, thus giving a visual indication that the contacts 2. 2:! have been bridged.

Also it will be observed that the bottom of the indicator plate has now separated from the block 9.

The indicator platc will now remain in the raised position until released by the operator.

After the solcnoid 6 has been deencrgizcd thus dropping armature ll). insulating block 9 and the contact bridge 8 to the lower position, the indicator plate 11 can be dropped to its initial position by pressing inwardly upon part 12!: of the latch plate thus moving the plate counter to the spring force and shifting the shouldered portion 12c to the right as viewed in Fig. 8. Plate 11 will now drop to its initial position and the shouldered portion 120 will once again bear against the surface portion 11a of the recess in the rear of the indicator plate.

in conclusion it will thus be evident that we have provided a novel and simplified arrangement for actuating the visual indicator component of an electromagnetic switching device through a desirably long stroke wherein the indicator is moved upward through an initial part of its stroke by the armature element of the electromagnet when the latter is energized while the remainder of the indicator movement in the upward direction is taken over and produced by the force of the spring element of the release or drop mechanism for the indicator.

Moreover, it is to be understood that while the particular embodiment of the invention as described and illustrated is preferred. various modifications of the structure may be effected without, however, departing from the spirit and scope of the inventive concept as defined in the appended claims.

We claim:

It A response indicating electromagnetic switch comprising stationary contact means, additional contact means movahle between initial and actuated positions, said additional contact means being engaged with and alternatively spaced from said stationary contact means, actuating means comprising an clectromagnet and armature for moving said additional contact means to its actuated position, an indicator plate means supporting said indicator plate for rectilinear sliding movement between an initial and a signal position corresponding to the respective positions of said additional contact means, said indicator plate including a recess at the rear which includes a surface with an initial portion parallel to the direction of sliding movement of said plate and which merges into a further portion inclined to the direction of sliding movement and terminating short of the end of said plate, a spring-pressed manually-releasable latch plate mounted for movement transverse to the direction of sliding movement of said indicator plate, a spring pressing said latch plate against the surface of the recess in said indicator plate for retaining said indicator plate in its signal position, and actuating means for said indicator plate operable on encrgization of said electromagnet to move said additional contact means to actuated position to move said indicator plate from its initial to its signal position; said indicator plate actuating means including said armature for imparting an initial displacement to mild indicator plate and said spring-pressed latch plate for effecting the remainder of displacement of said indicator plate to its signal position by engagement with the inclined surface portion of said recess after said initial portion of said recess has cleared said latch plate.

2. A response indicating electromagnetic swi ch as recited in claim 1, wherein the displacement imparted to said indicator plate by said armature effects relative movement of the same with respect to said latch plate to bring the latter into engagement with the inclined portion of said recess surface.

3. A response indicating electromagnetic switch as recited in claim 2. wherein said indicator plate supporting means mounts the same for vertical sliding mtr'enient, and said indicator plate is biased towards its init al position by its own weight, whereby said indicator plate returns to its initial position by gravity upon manual movement of latch plate in opposition to said spring.

References Cited in the file of this patent UNITED STATES PATENTS 470,697 Morse Mar. 15, i892 

